For more than 30 years, bodybuilders have taken tamoxifen to prevent and treat gynaecomastia caused by use of anabolic steroids.123 Usually, tamoxifen is sourced from the illicit market. However, bodybuilding discussion forums have speculated that a dietary supplement called Esto Suppress contains tamoxifen because the label listed one of its chemical names (figure⇓). Four samples were purchased at different times between late 2011 …

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